Standard
deviation
is
a
statistical
measurement
which,
when
applied
to
an
investment fund, expresses its volatility, or risk.
It
shows
how
widely
a
range
of
returns
varied
from
the
fund's
average
return
over a particular period.
For
example,
if
a
fund
had
an
average
return
of
5%,
and
its
volatility
was
15,
this
would
mean
that
the
range
of
its
returns
over
the
period
had
swung
between
+
20%
and
-
10%.
Another
fund
with
the
same
average
return
and
5%
volatility
would
return
between
10%
and
nothing,
but
there
would
at
least be no loss.